As the O.E. supplier of two-stroke pistons to KTM, Vertex pistons have an outstanding reputation for quality and performance. Each gravity-cast piston is created with only premium aluminum alloys utilizing an 12 - 21% silicon content.

The silicon content in Vertex pistons is crucial to the quality of the piston. Silicon is critical in decreasing thermal expansion which, when an engine reaches normal operating temperatures, can change the geometry of the piston. Controlling this expansion means that a Vertex piston can be run at tighter tolerances for more power, less noise and maintain a longer lifespan for the piston. Additionally, the silicon content decreases wear on the piston skirt which also aids in the longevity of the piston.

In addition to the silicon, each Vertex piston utilizes a unique Molybdenum Disulphide (MOS2) coating which aids in the break-in process and reduces overall wear.

With the purchase of a premium quality piston, every Vertex piston kit contains a complete set of nitride-coated or chrome-plated piston rings, a fully case-hardened wrist pin and circlips - all at a competitive price.

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36 Reviews

4.9 out of 5 stars

5 Star394 Star23 Star02 Star11 Star0

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...this wasn't my first Vertex piston kit nor will it be my last. High quality replacement piston that has given excellent service through the years. Husqvarna had been using them for years as OEM install and that's all the more reason to use them.

I immediately noticed huge power gains all the way from low end to top end. I have never had so much power on my 1998 Honda CR250 since I bought it. I am still at stock bore, too. Installation was a breeze. Rings fit perfectly. The piston clearance was spot on. I can hardly keep the front wheel on the ground now.

Although this says stock bore (2007 KTM125SX) keep in mind this is a B piston Vertex part #23928B so if you just got you cylinder replated, this is the wrong size, you need an "A" . No problem returning it, great customer service on the return but bad customer service when asked if this was an "A" piston and was told yes. Delayed my rebuild.

The quality is second to none, the power certainly noticeable...and on top of that the piston itself looks pretty cool too, excellent machine work. I would definitely recommend this piston to all my friends.

i now have2 of these vertex pistons on my full moded rm85 race bike and hope to get another for my newly brought rm 125!awesome light weight design,good friction coatingsingle ring performancegood lubricating mod holesvery good price for the deal you getcheersglenAustralia

The new ring and piston put the snap back in the bike so much had to let the little guy get use to the bike again. I could have got away with just rings but for the price might as well do the job right and not have to worry about it. The piston fit just like the guys said it would. Thanks

A: No, this would be for the piston kit only (no gaskets). Gaskets can be found in our OEM section for your bike.http://www.motosport.com/dirtbike/oem-parts/honda/2002/cr80

Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.

hotrod

Over 8 months agoLocation: Blackfoot Idaho

A: No you have to buy the gaskets separately . I use cometic gaskets .

JasonGraaf

Q: Drill holes?

1 year 5 months ago

For Wiseco pistons, the included instructions specify that 2 small holes must be drilled in the piston skirt to lubricate the exhaust bridge (2004 cr125). The Vertex piston instructions do not specify that this should be done, but I am cautious of leaving the exhaust bridge unlubricated. Should I drill the holes or not?

A: Yes this would be stock bore for your 1998 KX125. Just be sure to correctly select the Year/Make/Model of your bike before ordering so we can be sure to send you the correct piston for your bike. Also, feel free to give us a call at 888-676-8853 and we would be happy to help you out with your order.

Corey

Location: Fort Collins

Q: Stock Bore "B"?

2 years 10 months ago

My cylinder is stamped with a "B" on my 2011 YZ250. This is a stock bore, correct? The Vertex 2-Stroke Piston- Stock Bore is the correct size?

A: Yes, since this is a forged piston instead of a cast piston like your OEM piston was it does not have the "A, B, C" designation. It will work perfectly fine with the "B" cylinder on your YZ250 as forged pistons actual form to fit the shape/size of the cylinder when they are run through a heat cycle or break in period.

A: No gaskets included with this kit. You'll need a top end gasket kit as well.

MotoSportRyanT

ExpertMotoSport Staff

2 years 11 months agoLocation: Portland, OR, USA

A: This is actually just the Piston, Rings, Wrist Pin and Circlips. It would not include the Gaskets. We do offer several Piston Kits that would include the gaskets (see product recommendations).

Bunker

2 years 11 months agoLocation: Riverside, CA, USA

A: No you need to get gasket kit as well

Docproc

3 months 16 days ago

A: Mine did nor

FD3S

21 days agoLocation: Savannah,

A: No it does not come with gaskets. I recommend the OEM gaskets or Athena.

cr250chick

Top 500 ContributorTop 250 Contributor

Q: 2003 CR250 Piston fitment?

Over 3 years ago

I have an 03 CR250 and I just installed the Vertex piston (Stock Bore) that I bought here a few months ago. After only a few hours of riding I pulled the top and noticed it has been rubbing against the cylinder in the front where the exhaust ports are. I have an A cylinder and noticed the piston has a B on the top. When I ordered it there was only one option when it came to piston size but I'm guessing this is the wrong size for my cylinder. Is there an option for an A piston from vertex?